Lets say I can buy 200 of something for $20. but for $60, I can buy 750 of them. How can I quantify the money saved as cost per unit?

  • Besides the math to determine per unit cost, you might also need to consider the opportunity cost of having so many.

    • How long will the bulk supply last?
    • Is it something you will get tired of having?
    • How much space does it occupy?
    • Is it perishable?
    • Will it expire?

    • FuglyDuck@lemmy.world
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      1 year ago

      Is it perishable? Will it expire?

      used to work at Sam’s Club in highschool (yeah. it was awful then. I suspect it’s more-awful now). What people don’t want to know? those big ginormous tubs of mayo? they go bad rather quickly. Not like, rancid bad, but they’re definitely not as fresh or as worthwhile.

      Also the rotisserie chickens, bakery and meat are loss leaders to get you in the door. everything else they’re making huge profits on. Especially everything that’s at the front of the store- the bulk candy, the electronics, the seasonal things. those god awful t-shirts and disgustingly cheap tube tops.

      never by mayo in bulk. Also never buy the nacho cheese. Nobody needs a gallon-can of nacho-flavored valve sealant. just. trust me on that.

      • minorninth@lemmy.world
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        1 year ago

        Bulk mayo makes sense if you’re a restaurant or cafeteria or running a summer camp or something like that. Probably not for many other people.

      • lando55@lemmy.world
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        1 year ago

        What if I want to repair my roof, while at the same time feeling like my seats are too close to the concession stand at Fenway Park

        • FuglyDuck@lemmy.world
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          1 year ago

          They had serveral versions of tire sealant in the automotive section.

          They also had frozen “creamy potato soup” that contained no potatoes and didn’t need to be refrigerated.

          It’s been a while though.

    • goo@lemm.ee
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      1 year ago
      • Will you really use that many?

      I used to buy engine oil and filters in bulk, then car needed to be totaled. Difficult selling oil as a private.

  • WhoisJohnGalt@lemmy.world
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    1 year ago

    As others mentioned, it’s simple division. But to properly compare, you have to take into consideration the “units” in which you’re dividing.

    E.g. if you’re buying crayons, you can compare the # of crayons to the price. But if you’re buying chicken breasts, you can’t really compare the # of chicken breasts, but rather the ounces (or, whatever measurement of weight).

    • oo1@kbin.social
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      1 year ago

      this is basically the start point and at relatively close scales will work pretty well.

      this can also be expressed as a 2 in 10 (20%) bulk discount.

      you can add on adjustments if you can estimate other factors like the admin cost (of your time) per transaction, a defect rate cost or spoilage, cost of storage and transportation and so on.
      These overheads can sometimes be shared across other products, especially transport and storage.

      for longer term stuff you might want to translate this into an equivalent annual (or longer ) cost per year/day of consumption that covers expected consumption with your safety margin.

      if you need to account for every element of you cost base to the nearest penny then it can get pretty complicated - but if you’re prepared to make simplifying assumptions like:
      “It doesn’t spoil over time”,
      “I already have some unused space”,
      “i don’t need insurance on storage.”,
      “i’m going to ignore any adjustments lower than 0.001 cents per unit (a materiality threshold)”

      Whether those assumptions are a good idea or not, depends upon the wider context.

    • over_clox@lemmy.world
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      1 year ago

      You must be living in a perfect world to use math to answer this question. You’re assuming defective products don’t exist…

        • over_clox@lemmy.world
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          1 year ago

          Okay. Well is the item a food product or a tech product?

          Is it insured? What’s the cost to ship it back and get an exchange or refund if it’s a defective unit? Who pays to ship it back if so? How much does it cost to keep in storage until it sells?

          There are way more questions that need answers to even halfway try answering OP. Bananas need refrigeration, fidget spinners need little more than a box.

          OP didn’t say what they were looking to order in bulk, but doing simple arithmetic without sufficient information means basically squat.

        • over_clox@lemmy.world
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          1 year ago

          What’s the item in question? Is it apples (the actual fruit) or Nvidia graphics cards?

          They’re not gonna have the same failure rate. To assume everything has the same failure rate is a failure in data analysis.

          • Skua@kbin.social
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            1 year ago

            You misunderstand. Assuming you’re buying 200 of product A or 750 of product A, you should expect the same proportion to be defective. Nobody’s suggesting two entirely separate products should have the same failure rate, but the question is also not about comparing two entirely separate products

            • over_clox@lemmy.world
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              1 year ago

              You totally missed my point. OP didn’t even distinguish whether they’re looking to purchase produce (which has a short shelf life), or looking to purchase electronics or mechanical devices (which tend to have a fairly long shelf life).

              It costs either way to keep items on the shelf. But, like, what’s it cost to keep the items on the shelf long enough to sell them without half your stock rotting away?

            • over_clox@lemmy.world
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              1 year ago

              Point is, there’s a missing factor here. How much does storage price cost?

              No way to know if OP can’t tell us whether it needs constant refrigeration or not. That drastically changes the prices yo.

        • over_clox@lemmy.world
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          1 year ago

          Yes, Meg is a defective product as well, yet somehow she still makes money. Maybe they should have got a refund…

  • SHITPOSTING_ACCOUNT@feddit.de
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    1 year ago

    For cost per unit, you divide the cost by the number of units. $20/(200 units) = $0.10 per unit. $60/750= $0.08, so 2 cents cheaper per unit.

    But if you actually only need 50 but can’t resist a “good deal”:

    The 200 cost $0.40 per item that you actually need, the 750 cost $1.20 per item that you actually need (plus the cost of storing and at some point throwing out the ones you don’t need).

  • Smokeydope@lemmy.world
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    1 year ago

    Total Cost of batch / quantity of items = cost per individual item. 20 dollars /200 items =10 cents per item 60$/750item= 8 cents per item. It will be helpful for you to let this equation roll in your brain for a bit and try to understand why it is true maybe.

    Geometrically the same exact idea can be visualized. you can think of total cost $ being the length of a line segment, and the quantity of items as equally split portions of that line seg. If you have a total cost of 1$ (a line seg with length of 1) and get two items, the cost of each item is 50c, or the line will be partitioned equally in two exactly In half. If you had three items the line would be split into thirds and so on.

  • spongebue@lemmy.world
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    1 year ago

    cost per unit

    This right here answers your own question. The word “per” implies division in math. Cost per unit = cost divided by units. If cost is $20, and units is 200, that means you have $20 / 200 = $0.10.

    Similarly, 150 miles per 2 hours is 150 miles / 2 hours = 75 miles / 1 hour = 75 miles per hour

    Other math vocabulary hints: and means addition (3 and 5 is 8) and of means multiplication, typically with a fraction (half of 6 = 1/2 * 6 = .5 * 6 if you prefer = 3

  • UntouchedWagons@lemmy.ca
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    1 year ago

    200 for $20 is $0.10 each (200 for 2000 pennies) while 750 for $60 is $0.08 each (750 for 6000 pennies) so you save 2 cents per item. Or you got 150 items for free by buying the 750 pack.